Gaming machine with video mode payoff multiplier

ABSTRACT

A spinning reel slot machine gives a multiplied payoff when certain conditions are fulfilled. Wins including a special symbol on the pay line are multiplied by a multiplier value generated according to the rules of a secondary game. The secondary game is a computer simulation or a video display of a set of reels which simulate the operation of a physical set of reels, and have symbols representing different numerical values. The values on the computer generated reels when they stop are multiplied together to generate the multiplier.

BACKGROUND OF THE INVENTION

[0001] This invention relates to gaming machines. More specifically, itrelates to spinning reel type slot machines..

[0002] Spinning reel slot machines have maintained their popularity,evolving from electromechanical devices to the present day devices whichemploy microprocessor control. In modern devices, the spinning reels areused merely as a display to advise a player if she has won or lost agame of chance played entirely in a computer memory according to therules embedded in a computer program. Such machines may have furtherdisplays, in addition to the reels, on which other aspects of the gameare displayed. In the past, such displays have included “trail games”wherein an indicator proceeds along a board game style trail providingdifferent features. These features might include nudges and additionalgamble features awarding prizes.

[0003] Spinning reel slot machines generally provide different symbolson each of the reels, and give payoffs when a plurality of the symbolsdisplayed in a certain position on each reel, are the same. The relevantposition is usually along a horizontal line referred to as the payline.However, other payoff schemes have been developed. For example, U.S.Pat. No. 5,205,555 (Masahiro) discloses a machine with values on thereels, instead of symbols. A mathematical operation is performed onvalues displayed on the payline to determine the value of an award. Thistype of scheme has the disadvantage that it is not easily understood byregular players of the slot machines, who are used to a system ofsymbols and payoffs.

[0004] It has also become common practice to provide spinning reel slotmachines with a secondary game which is activated only when certainspecial symbols appear in winning. combinations. Frequently, thesecondary game will be provided on a dot matrix screen disposed abovethe reels, and will be generated by a computer program. Often, duringthe course of the operation of the secondary game, a multiplier isestablished, by which the standard payoff for the winning combination ismultiplied to provide the actual payoff. A game with such a feature isdiscussed in U.S. patent application Ser. No. 8/998,139 also assigned tothe present assignee. This type of game has the advantage that biggerjackpots can be provided when both a winning combination on the reelsand a high multiplier on the feature occur, because such occurrences canbe made to be very rare. It is important that this feature is simple tounderstand and exciting so that a player will choose the machine inquestion over other spinning reel slot machines.

[0005] It is also important that it is straightforward for a machineoperator to adjust the payoff rate, and it is therefore advantageous inthe payoff rate is related to the parameters used in the payoff tablesin as simple a way as possible.

[0006] Spinning reel slot machines known in the art pay out wins at aset rate per second. This rate is generally fairly slow to give theimpression that a lot of credits are being paid out, and to increase theinterest of other players in the machine. However, this slow payoff ratecan be annoying to players who are well acquainted with the game andwish to resume play as soon as possible. The present invention providesa player selectable payoff rate.

SUMMARY OF THE INVENTION

[0007] In a first aspect, the present invention is a spinning reel slotmachine in which selected payoffs are multiplied by a variable valuewhich is independent of the winning symbol combination whereby toincrease player interest in the game.

[0008] By multiplying the payoff for selected wins by a variable value,the maximum possible payoff achievable is increased significantly,whereby increasing player interest. However, as only selected payoffsare multiplied by the variable value, the overall payoff is notincreased significantly. Furthermore, as the variable multiplier is notdependent on the selected payoff, it is very straightforward tocalculate and modify the overall payoff of the machine.

[0009] The present invention provides a spinning reel slot machine whichprovides a secondary game when certain conditions are met in thecombination of symbols displayed on the reels after a spin. Thesecondary game takes place on a display and involves the simulation of aset of reels on the display. The spinning of these reels is simulatedand the combination of symbols which results from the simulated spin isused to generate a multiplier for a payoff obtained in the spin of theactual reels.

[0010] In a specific implementation of the invention, the symbolssimulated on the reels are numerical values and the product of thesevalues is used as the multiplier.

[0011] In an a adaptation of this implementation, if a multiplier valueof 1 is obtained, the multiplier is increased to 2, so that a multipliergreater than 1 is always obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a simplified illustration of a spinning reel slotmachine according to a preferred embodiment of the present invention.

[0013]FIG. 2 is an enlargement of the slot machine display showing howphysical symbols appear on, above and below the payline in the preferredembodiment.

[0014]FIG. 3 is a flowchart showing a specific embodiment of thepreferred embodiment of the present invention.

[0015]FIG. 4 is a table showing three sets of 22 symbols on the threereel strips according to a specific example of a first embodiment of thepresent invention.

[0016]FIG. 5 is a table showing the prizes awarded in the four modes ofthe example of the first embodiment.

[0017]FIG. 6 shows the contents of the display shown in FIG. 1 duringoperation of a secondary game.

[0018]FIGS. 7a, 7 b and 7 c are tables showing reel strips used tocalculate a multiplier value.

[0019]FIG. 8 is a table showing a reel strip mapped onto by the reelstrip of FIG. 7c.

[0020]FIG. 9 is a table showing the expected payoff for each winningcombination in each mode, the sum of the expected payoffs, and thepercentage total payoff.

[0021]FIG. 10 is a flowchart representing the payoff scheme of aspecific embodiment of the present invention.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT OF THE INVENTION

[0022]FIG. 1 shows an overall view of a first embodiment of the presentinvention, there is provided a spinning reel slot machine 2 comprising acabinet 10 having windows 12, 14, 16 on the front which can be viewed bya player standing in front of the machine. As in most spinning reel slotmachines, behind the window three reels 22, 24 and 26 are mounted forrotation. A portion of the outer surface of each reel is visible throughthe corresponding window as shown in FIG. 2. Each reel has 22 regularlyspaced locations which either have symbols represented thereon or areleft blank. The spatial allocation of these symbols is shown in FIG. 4.Each window is preferably dimensioned to display three consecutivelocations on each reel at a time. The reels are each individually drivenby a stepper motor which is controlled by a microprocessor as is knownin this art. Circuitry is provided so that the microprocessor can sendinstructions for the reel to spin and to stop at a predeterminedposition. As shown in FIG. 2, whenever all the reels are stopped, athree-by-three rectilinear array of symbols is displayed. The row ofthree symbols across the center of this three by three array is deemedto be located on the payline 20, and the symbols appearing on this linedetermine the prizes paid out as described below. For a typical 22 stopreel, the symbols and frequency of occurrence are selected based onprobability analysis. These symbols are designed in an eye-catchingmanner.

[0023] A handle 21 or a switch button is provided on the machine, bywhich a player can commence cycles of the game after inserting money ortokens to buy credits.

[0024] To operate the game, a player puts coins or bills into the gameand the value is determined by the processor and stored in computermemory. The number of credits thus purchased is displayed on anotherdisplay not shown. Depending on how many modes the game has, differentswitch buttons are provided to start the game in the appropriate mode.

[0025] If sufficient credit has been purchased, the handle 21 can bepulled or the appropriate switch button operated. This commences a cycleof operation of the machine, whereby the reels 22, 24, 26 begin to spinunder the control of the game microprocessor. The machine enters themode corresponding to the number of credits which have been wagered, anddeducts the appropriate number of credits from the stored value.

[0026] The operation of the game when a cycle of operation is commencedis hereinafter described with reference to FIG. 3. The microprocessorgenerates one or more random numbers to determine what the symbols onthe payline will be. Typically, the memory contains a look up tablerepresenting the symbols, as shown in FIG. 4. The processor assigns thesymbols shown to registers in memory for use in calculating the payoff.The microprocessor then determines if the combination is a winningcombination as described in detail below, and calculates any payoffdepending on the symbols showing. A specific example of such acalculation is described later. Typically, payoffs are all based onmultiples of the smallest number of credits needed to play a game.However, some additional inducement may be expressed to encouragemultiple credit play.

[0027] Once all calculations have been done, the microprocessor spinsthe reels and causes the reels to stop at the appropriate locationscorresponding to the random number selected for each reel. Usually, theprocessor stops the left reel 22 first, followed by the center reel 24and finally the right reel 26. When the reels have stopped spinning, anywin is displayed and the payoff is ether released into a coin dischargetrough 28 or added to the stored credits.

[0028] An example of a specific embodiment will now oe described indetail. It has four modes of play referred to as 1 Coin, 2 Coin, 3 Coinand MaxBet modes and requiring 1, 2, 3 or 4 credits. respectively.

[0029] The symbols in this example of the embodiment are 1BAR, 2BAR,3BAR, MEGA, STAR, SEVEN and BLANK, and their distribution on the reelstrips is shown in FIG. 4. The bar symbols are referred to genericallyas BARS.

[0030] The normal payoff for any winning combination on the payline 20is shown in the table of FIG. 5. The prize paid out for each of thewinning combinations listed in the columns labeled Reel 1-Reel 3 isshown in the 1 Coin, 2 Coin, 3 Coin and MaxBet (4 coins) columns anddepending on the number of credits bet. The game program checks theselected combination against each of the combinations in FIG. 5,starting with the highest paying win at the top of the table andprogressing to the lowest paying win at the bottom. The numeric valuerepresenting the payoff is a multiple of one credit. As can be seen, theMEGA symbol is wild and can replace any symbol in a winning combination.

[0031] Importantly, when a winning combination including a MEGA symboloccurs on the payline, a secondary game is commenced in a dot matrixdisplay 44 shown in FIG. 1, which generates a multiplier value by whichto multiply the secondary payoff associated with the winningcombination.

[0032] When the secondary game is commenced by the occurrence of theMEGA symbol, graphical representations of three reel strips are shown onthe display 44, as shown in FIG. 6. The computer generated reel stripsof the secondary game have 36 symbol locations. They do not show symbolsas do physical reels 22, 24 and 26, but instead show multiplier values.Examples of these computer generated reel strips are shown in FIGS. 7aand 7 b. In this example, these multiplier values for each reel rangefrom 1 to 3 in FIG. 7a and 1 to 5 in FIG. 7b. The multiplier value 1 maybe represented by a blank display, as multiplication by one has noeffect on the resulting payoff. Thus, the middle reel strip in itconfiguration shown in FIG. 6 represents the number 1.

[0033] The microprocessor runs a computer program, discussed further inconnection with FIG. 10, which generates visual representations ofspinning reels on the display 44. The microprocessor, as with thephysical reel selection, generates random values representing thepositions (multiplier values) which it will display. The computerprogram stops the animations at the appropriate time to display theselected multipliers across the payline of the video simulated reeldisplay.

[0034] The multiplier values displayed along the payline are multipliedtogether to produce a combined multiplier value X by which the regulargame payoff will be multiplied. For example, if the regular payoff is 30credits, and multiplier values displayed on display 44 are 2, blank and3, as shown in FIG. 6, the multiplier value will be 6 (2×1×3), and thepayoff will be 180 credits (6×30).

[0035] The mean of the values on each of the reel strips are μ₁ μ₂ andμ₃. it is elementary to show that the expected value for the multiplierX is as follows:

X=μ ₁μ₂μ₃  (1)

[0036] However, if all the symbols in the computer generated payline areblank (ie. all the values in the payline are 1), this multiplier value Xwill be 1 . The player would not then receive an enhanced payoff forachieving a MEGA symbol in the physical reel game. In order to overcomethis, in the event that the product of the three multiplier values ofthe computer generated reels is 1, the value of multiplier X isarbitrarily set to 2.

[0037] If the probabilities of obtaining a 1 on each of the computergenerated reel strips is p₁, p₂ and p₃ respectively, it isstraightforward to show that the expected value_(m)X of the modifiedmultiplier will be:

X _(m)=μ₁μ₂μ₃ +P ₁ P ₂ P ₃  (2)

[0038] In the case of this specific embodiment, one set of computergenerated reel strip values is used in the first three modes (FIG. 7a),and a different set is used in the MaxBet mode (FIG. 7b). The computergenerated reel strips used in the first three modes have values rangingfrom 1 to 3. The maximum multiplier which can be obtained with such arange of values is accordingly 27. The expected multiplier valuegenerated by these reel strips is referred to hereinafter as X₁. Usingequation 2, it is easy to calculate the value X₁, with the values of thereel strips shown in FIG. 7a. The expected value of X₁, is 4.44.

[0039] The computer generated reel strips of the MaxBet mode are shownin FIG. 7b, and contain values from 1 to 5. The maximum multiplier whichcan be obtained with such a range of values is accordingly 125 . If thismultiplier value is obtained in conjunction with the maximum payingwinning combination of 200 credits, a win of 25,000 credits can beobtained. The expected multiplier value generated by the sets of valuesshown in FIG. 7b is referred to hereinafter as X₂. Using equation 2, itis easy to calculate the value X₂, with the values of the reel stripsshown in FIG. 7b. The expected value of X₂ is 7.08.

[0040] Instead of the arrangement shown in FIGS. 7a and 7 b, an extendedreel with mapping can be used for the secondary games as shown in FIGS.7c and 8. The extended reel allows greater flexibility in the display ofmultiplier values on the simulated reel display 44. This allows the gameto be percentaged more easily and makes for a more exciting displayabove and below the simulated payline. The extended reel can either havea larger number of “stop” positions or a mapping scheme can be utilized.In the latter case, for example, the 36 “stops” are mapped to a fewprearranged video display frames of reel strips as represented in FIG.8. Increasing the number of stops mapped to the frames allows changes inthe hold percentage.

[0041] Referring to FIG. 5, note that the payoff formula for the 3credit mode is the same as the same as the payoff formula for the 4Credit mode. However, payoff in the 4 credit (MaxBet) mode is increasedbecause the expected multiplier value X₂ (7.08) is significantly greaterthan the expected multiplier value X₁, (4.44).

[0042] The overall payoff of the machine in each of the four modes caneasily be calculated by multiplying the expected payoffs for each of thesymbol combinations shown in the “Predicted Value” columns of FIG. 5 bythe proportion of the reel combinations which will generate each payoff,and then summing the result. These products, and the relevant sums areshown in FIG. 9 for each of the four modes. Dividing these sums by thenumber of credits per play for each mode yields, and multiplying by 100yields the percentage payoff in each case, and the associated percentagepayoffs are also shown in FIG. 9. The proportion of the reelcombinations which will generate each payoff is calculated by dividingthe number of reel combinations yielding that payoff value, as shown inthe “No of ways to achieve” column of FIG. 5, by the total number, ofreel combinations, which in this case is 10,648 (22³).

[0043] It can be seen from the Percentage Payoffs shown in FIG. 5 thatin this example it is more advantageous for a player to play in the 3credit mode than the 2 or 1 credit mode, and it is even moreadvantageous to play in the 4 credit mode. The reason is it moreadvantageous to play in the 3 credit mode than the 1 or 2 credit modesis that the payoff for a STAR MEGA STAR win (200X₁) isdisproportionately larger than the values in the other two modes (60X₁and 120X₁).

[0044] The procedure followed when a win is paid out is shown in FIG.10. When the machine pays out after a win, a predetermined time delay isprovided between the counting out of each credit to be paid. In thisexample the standard delay is 120 milliseconds (ms) per credit. However,if the game is in MaxBet mode, this delay is automatically set to 90 msper credit, as more credits are likely to be won, and the player islikely to be more of an expert at the game.

[0045] In any case, if the player presses the MaxBet mode button afterthe reel spin is complete and before or during credit pay out, the delayon the remaining credits is set to 12 ms per credit won. FIG. 10illustrates the program flow chart permitting the implementation of thisenhanced payout feature.

[0046] In modifications of the described embodiment, different valuesfor the prizes and different symbols on the physical reels could beused. More reels, could be provided to provide more combinations, ormore symbols could be provided on each reel. Extra features, such asnudges and holds, well known in the art could also be added to enhancegameplay.

[0047] While the invention has been illustrated and described in detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character, it being understoodthat only the preferred embodiment has been shown and described and thatall changes and modifications that come within the spirit of theinvention are desired to be protected.

What is claimed is:
 1. A gaming machine including a set of spinningreels having a plurality of symbols thereon, means for spinning andstopping said reels to display symbols on a payline, means for payingout prizes, means for displaying a secondary game, and a processoroperating according to a game program for controlling the spinning andstopping means, said processor including: a) means for randomlyselecting symbols to be displayed by said spinning reels; b) means fordetermining if the selected symbols constitute a winning combination,and, if so, a corresponding standard prize amount; c) means forinitiating play of a secondary game to generate a multiplier value, if aspecial symbol is included in said winning combination; d) means forcalculating the prize to be awarded for said winning combination basedon the standard prize amount multiplied by said multiplier value, if thewinning symbol combination includes said special symbol; said means forinitiating play of said secondary game including: i) means for randomlyselecting at least two numerical values to be displayed by saidsecondary game; and ii) means for multiplying the numerical values togenerate said multiplier value.
 2. A gaming machine according to claim 1wherein said means for randomly selecting at least two numerical valuescomprises means for simulating reels on said display means, saidsimulated reels having symbols representing different numerical values.3. A gaming machine according to claim 2 wherein said means forinitiating play of said secondary game further includes means forsimulating the spinning of said reels before displaying said randomlyselected numerical values.
 4. A gaming machine according to claim 1wherein said means for playing a secondary game increases saidmultiplier value if it is not greater than a certain predeterminedvalue.
 5. A gaming machine according to claim 4 wherein thepredetermined value is
 1. 6. A method of operating a gaming machineincluding a set of spinning reels having a plurality of symbols thereon,means for spinning and stopping said reels to display symbols on apayline, means for paying out prizes, means for displaying a secondarygame, and a processor operating according to a game program, comprisingthe steps of: a) randomly selecting symbols to be displayed by saidspinning reels; b) determining if the selected symbols constitute awinning combination and a corresponding standard prize amount; c)initiating a secondary game to generate a multiplier value if a specialsymbol is included in said winning combination; and d) calculating theprize to be awarded for said winning combination based on the standardprize amount multiplied by said multiplier value, if the winning symbolcombination includes said multiplier symbol; said secondary gamecomprising the steps of: i) randomly selecting at least two numericalvalues; ii) displaying said values; and iii) multiplying the numericalvalues together to generate said multiplier value.
 7. A method ofoperating a gaming machine according to claim 6 wherein said steps ofrandomly selecting at least two values and displaying said valuescomprises displaying a representation of at least two spinning reels onsaid display having said numerical values thereon.
 8. A method ofoperating a gaming machine according to claim 7 wherein said step ofdisplaying a representation of at least two spinning reels furthercomprises displaying a simulation of the spinning of said reels beforedisplaying said randomly selected numerical values.
 9. A method ofoperating a gaming machine according to claim 6 wherein said means forplaying a secondary game increases said multiplier value if it is notgreater than a certain predetermined value.
 10. A method of operating agaming reel slot machine according to claim 9 wherein the predeterminedvalue is
 1. 11. A gaming machine including a set of spinning reelshaving a plurality of symbols thereon, means for spinning and stoppingsaid reels to display symbols on a payline and a processor operatingaccording to a game program for controlling the spinning and stoppingmeans, said processor including: a) means for randomly selecting symbolsto be displayed by said spinning reels; b) means for determining if theselected symbols constitute a winning combination, and, if so, acorresponding prize amount; and c) means for paying out said prize as aplurality of credits; said means for paying out prizes including meansfor providing a delay between payment of successive credits, and meansfor adjusting said delay.
 12. A gaming machine according to claim 11wherein said game program provides different modes which can be selectedby a player of said game, and wherein said means for adjusting saiddelay adjusts said delay in accordance with the mode selected.
 13. Agaming machine according to claim 11 wherein said means for adjustingsaid delay comprises a player operable input device.
 14. A method ofoperating a gaming machine including a set of spinning reels having aplurality of symbols thereon, means for spinning and stopping said reelsto display symbols on a payline, and a processor operating according toa game program for controlling the spinning and stopping means, saidmethod of operating comprising the steps of a) randomly selectingsymbols to be displayed by said spinning reels; b) determining if theselected symbols constitute a winning combination, and, if so, acorresponding prize amount; c) paying out said prize as a plurality ofcredits; wherein said step of paying out prizes comprises a further stepof providing a delay between payment of successive credits, andadjusting said delay.
 15. A method of operating a gaming machineaccording to claim 14 wherein said game program provides different modeswhich can be selected by a player of said game, and wherein said step ofadjusting said delay comprises adjusting said delay in accordance withthe selected mode.
 16. A method of operating a gaming machine accordingto claim 14 wherein said gaming machine comprises user operable inputmeans, said step of adjusting comprising adjusting said delay inresponse to operation of said user operable input means.